Pertinent prior art systems include U.S. Pat. No. 4,002,973, "Elevator Testing System", which produces "artificial control signals", which are used with a volt/ohm meter to check the continuity of the various electromechanical contacts in the elevator control system. This patent does not contain any of the basic elements of the new invention.
Another prior art U.S. Pat. No. 4,401,192, "Method of Evaluating the performance of an Elevator System", provides an elaborate "simulator system which simulates the operation of an elevator system having the same building configuration, number of elevator cars and which generates data that is representative of the proper response of the elevator system" . . . .
This system does not anticipate the use of a digitally produced graphic output presentation, such as the new invention, which shows the interaction of many cars in the system.
There is U.S. Pat. No. 4,750,591, "Elevator Car Door and Motion Sequence Monitoring Apparatus and Method", which claims, essentially, "Apparatus for monitoring an elevator, comprising signal processing means, for monitoring the states of a plurality of two state parameter signals, each indicive of one of a corressponding plurality of elevator parameters . . ." This patent also does not anticipate the use of a graphic presentation to show the interrelated operation of a number of elevator cars; such as provided by the new invention.